Amalgamator



April 14, 1953 R. P. FISHER ETAL 2,634,860

AMALGAMATOR Filed Aug. 12, 1950 IN V EN TORS ROBERT P FISHER ORV/LLE E. WALL/N6 Patented Apr. 14, 1953 AMALGAMATOR Robert P. Fisher, Los Angeles, Calif., and Orville E. Walling, Beatty, Nev., assignors to Paramount Mining and Milling Company, Beatty,

Nev., a copartnership Application August 12, 1950, Serial No. 179,022

Claims. 1

This invention relates to devices for separating precious metals from other metals and minerals with which it may be mixed, and is particularly directed to a novel and improved form of an amalgamator for accomplishing such separation.

For many years, a process known as amalgamation has been practiced for separating precious metals from the rock through which they are distributed. In general, this process comprises the pulverizing of the rock and bringing it in contact with mercury. Precious metals, such as gold, having a high affinity for mercury, are trapped by the mercury forming amalgam, while the rock, lacking such an affinity, passes through or over the mercury. The amalgam thus produced may be retorted, the mercury being distilled off and the precious metal left behind; or in many cases, the amalgams themselves have useful industrial applications.

Numerous devices have heretofore been utilized to perform the amalgamation process as hereinabove set forth, but, in general, such devices possess certain inherent shortcomings which make it virtually impossible to either run the;25

process at high speeds over continuous periods of time or to effectively remove all the metal from the rock mixture. As is known in the art, the more common amalgams are formed from a combination of mercury with gold, silver, bismuth, cadmium, copper, or tin. Although some amalgams are formed when the metal and mercury are placed together in a dilute acid, or by adding mercury to the solution of a metallic salt, the present invention is primarily concerned with amalgams formed by direct contact of a metal with mercury. Some of the more readily ascertainable difficulties encountered in apparatus designed to produce the latter type of amalgams have been the failure of all parts of the precious metal to contact the mercury thereby decreasing the efficiency of the unit, or permitting the mercury to flower resulting not only in a loss of particles of mercury and newly formed amalgam, but also permitting particles of precious metal to pass through the mercury in an unobstructed flow path.

It is therefore an object of the present invention to provide apparatus for producing amalgams in which all of the metal being processed is required to pass through a layer of mercury, and in which the mercury will, at all times, completely fill the passage through which the metal must travel.

Another object of the invention is to provide mechanism of the character described in which 2 no moving parts are provided, thereby increasing the useful life of the apparatus.

A further object of the invention is to provide a device of the aforesaid type which is of extremely simple construction, and which may be operated in a continuous flow process over extended periods of time only requiring a shutdown when it is desirable to remove the formed amalgam therefrom.

Yet another object of this invention is to provide in apparatus of the type described, means for preventing flowering of the mercury during operation, but which will not unduly interfere with the quantities of metal entering the apparatus.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to the drawing:

Figure 1 is a cross-sectional view of the apparatus of the present invention taken along the plane indicated by line ll of Figure 2.

Figure 2 is a top plan view of the device, portions of the drawing being broken away in order to more clearly illustrate the internal construction.

Figure 3 is a cross-sectional view of a portion of Figure 1 and indicating a modified form of cone arrangement.

The apparatus disclosed herein is arranged to receive pulverized rock and metal, for example, from a pulverizer of the type disclosed in the application filed cotemporaneously with this application, mix the pulverized material in a liquid vehicle, force the same under pressure through a layer of mercury whereby the metal will combine with and be trapped by the mercury while the rock and vehicle will be permitted freely to pass therethrough and be discharged through a suitable outlet.

The embodiment of the invention illustrated in the drawing for performing the foregoing, includes a tank II of any desired shape, which is arranged to receive the pulverized rock and metal through a conduit l2 which may be indirect flow communication with the discharge outlet of a suitable pulverizing mechanism. A conduit I3 connected to a source of water is also connected to the tank, and by means of a valve l4, controlled amounts of water can be supplied to the pulverized material so as to provide a liquid carrier for the material as it is further processed.

The amalgamator mechanism generally indicated by the numeral I6 is constructed very simply, and as here shown, comprises a cylindrical casing which includes a side wall ll, a dished bottom wall l8, and a removable top cover plate IS. The plate I9 may be secured to the wall H by means of circumferentially spaced bolts or screws 2! threadely engaged to the cover and to a horizontal flange 22 extending radially outwardly from side wall ll. If desired, an annular gasket 23 may be interposed between the cover plate and flange in order to prevent leakage therebetween when the process is being carried out. Support means may also be provided in order to raise the dished bottom wall l8 above the surface of the ground or other base structure, and such means may include a plurality of legs constructed of pipe or other structural member,

although the illustrative ,mechanism discloses four strap iron legs 24 welded or otherwise secured to equally spaced portions of the wall l1, and bent radially outwardly as at 26 and terminating in horizontally disposed feet portions 21.

When the cover plate is operatively inserted on the casing [6, an enclosed chamber 28 will be defined thereby, and operatively inserted in such.

chamber is an open end cylindrical baflle member 29 spaced from side wall ll so as to provide an annular passage 3| therebetween. Member 29 may be secured to cover plate by means of welding or the like, and it will be noted that the lower end of the members is spaced from bottom wall 58 of the casing whereby chamber 28 and passage 3| may be maintained in flow communication. Mounted on the bottom wall I8 in centra ly disposed relation is a conical member 32 with the apex thereof also extending into chamber 28. This latter member constitutes an important element of the amalgamator and its function will be hereinafter described.

Prior to the time the amalgamator is placed in operation, a quantity of native or liquid mercury is inserted in the casing which may be accomplished by removing cover plate l9, or by providing an access door in the plate or casing. The amount of mercury thus added must be sumcient to extend above the plane'defined by the lower edge 33 of bafiie member 29 so that the passage 3! will be effectively isolated from chamber 28 by the mercury. It will thus be evident that if the pulverized material is forced to flow from the passage to the chamber, it must pass through the mercury loath wherein amalgamation of the gold or other metal may take place. To accomplish the foregoing, means are provided for continuously introducing the liquid and pulverized material from tank I l into passage 3|. As was previously mentioned, water may be used as the vehicle for carrying the material to the amalgamator, and, if desired, certain chemicals may be added to the mixture to promote amalgamation, but the particular nature of such chemicals is not believed pertinent in this application. As here shown, such means include a pump 34 operatively inserted in a conduit 36, which in turn is secured to casing wall I in any suitable manner, such as by threaded engagement to a sleeve 31 attached to the wall. In this manner, upon actuation of the pump, the pulverized material in its liquid carrier will be drawn from tank ll, forced through conduit 36 into passage 31 from which it will be required to pass through the mercury and upwardly into chamber 28. In order to control the pressure of the incoming material, a pressure regulating valve 38 is inserted in conduit 36 on the discharge side of the pump, and a gauge 39 is also installed in order to indicate the operating pressure.

As was heretofore explained, the mercury will combine with the gold or other metal to form amalgam, while the remaining waste material consisting of pulverized rock and its liquid carrier will pass therethrough into chamber 28. Means are provided for constantly discharging the waste material from the chamber and includes a conduit M in flow communication with the chamber which may extend through the casing wall H to a suitable dump tank, sewer or the like. Conduit 4| may be threadedly engaged to an internally threaded sleeve 42 secured to the baffle member 29, and extends through an aperture formed in wall I! which is provided with an externally threaded sleeve 43. To prevent leakage from the passage 3! through this latter member, a cap 44 is secured thereto, and a gasket 46 is operatively inserted between sleeve 53 and the cap. To control the discharge pressure, a valve All is inserted in conduit 4|, and by means of a gauge 48, the pressure at the discharge end of the amalgamator can be readily ascertained.

For increased operating efficiency, it is desirable to maintain a relatively high pressure on the material entering the amalgamator, as it is evident that the quantity of material processed will be generally proportional to the pump pressure. With the types of amalgamators previously used, it was found necessary to reduce such pressures due to the danger of the mercury flowering as increased loads of material were passed therethrough. However, by means of the conical member 32 as disclosed herein, such flowering is substantially prevented, and no blows will be created which result in loss of mercury and amalgam through the discharge conduit, and also permit quantities of the pulverized metal to pass directly through the openings created in the mercury and be lost through the discharge opening.

According to the present invention, as the pressure in passage 3| is increased, the mercury will tend to rise along the outer surface of the cone until it reaches the apex thereof. As mercury has a natural affinity for itself, the cone may be completely covered by the mercury under some conditions of operation. In any event, the relatively steep slope of member 32 will create a pressure head on the mercury adjacent the lower portions of the cone and prevent particles of the mercury from being blown free and through the discharge, with the aforementioned undesirable results. It will also be noted that the spacing between the surface of the cone and the inner edge of the bottom of baffle member 33 is substantially smaller than the passage 3!, thereby presenting a restricted flow path to the material being amalgamated and assisting the cone action in preventing the mercury from flowering. In normal operations, both of the gauges 39 and 48 will indicate approximately 14 p. s. i. pressure, such pressure having been found most efficient for operation of the device.

In Figure 3 is disclosed a modified form of cone member which has certain advantages over heretofore described element 32. This embodiment includes a substantially conical member 53 mounted on base plate IS in a manner similar to was 3? A mercu y fiQw-retarder is secured to member 53 adjacent the apex thereof and comprises a circular plate 54 of slightly concave crosstilization. It has been determined that at temperatures above 32 degrees Fahrenheit, a certain amount of volatilization will occur, and also that the mercury is more susceptible to flowering. We have therefore provided one or more refrigeration coils 51 which may be placed either in chamber 28 or around the wall I? in close proximity to the mercury. A suitable refrigerant such as brine, ammonia, or the like is caused to circulate through the coils so as to maintain the temperature of the mercury in the approximate range of 20-32 degrees Fahrenheit. For purpose of simplicity, the drawing merely indicates the coils, as the pumps, compressors, or other refrigeration accessories form no part of the present invention.

After the process has been carried on for a period of time, the newly formed amalgam may be removed from the casing by removing plugs 5! normally engaged in threaded apertures provided at spaced intervals in the cone member. These plugs may be grasped by removing a centrally disposed plug member 52 threadedly engaged to a sleeve 53 provided on bottom wall I3. The amalgam may be allowed to run into any suitable receiver, and may then be further processed according to the particular requirement at the time. Also, if desired, the bottom wall l8 may merely comprise an annular ring, the inside diameter thereof being defined by the cone base. In this manner, plug member 52 may be eliminated, and the amalgam drained from the device simply by removing the plug members 5|.

It is also to be noted that the foregoing apparatus is also capable of separating materials which do not possess an aflinity for mercury. This may be accomplished by controlling the pressures so that the pulverized material of a higher specific gravity will be unable to pass through the mercury, while the lighter materials may pass therethrough and be discharged through conduit 4|. Thus, by arranging several of these units in series, physical separation of all of the different materials can be readily effected.

What is claimed is:

l. A device of the character described comprising a generally cylindrical casing including a top, bottom and side Walls, a cylindrical baffle member within said casing defining an inner chamber and spaced from said side wall to define an annular passage therebetween, one end of said baffle member being immediately adjacent said casing top wall and the other end thereof being spaced from said casing bottom wall to provide for flow communication between said annular passage and said chamber adjacent the bottom end of the latter, inlet means including a conduit opening into said annular passage, outlet means including a conduit extending through said passage and opening into said chamber, and a conical member mounted on said casing bottom wall with the apex thereof disposed above the lower end of said bafile member and the sides thereof spaced from the baflle member to define therewith a restricted passage of smaller cross-sectional area than said annular passage.

2. Apparatus for amalgamating a pulverized metal mixed with foreign matter in a liquid carrier including an enclosed cylindrical casing having a side wall, bottom wall and top wall, a cylindrical member within said casing defining an inner chamber and an annular outer chamber, means defining a circumferentially extending passage between said inner and outer chambers adjacent said bottom wall, inlet means opening to said outer chamber and vertically spaced from said bottom wall, discharge means passing through said outer chamber in fiow communication with said inner chamber and vertically spaced from said bottom wall, means for delivering said mixture to said inlet means under pressure, mercury disposed in said chambers adjacent said bottom wall and completely filling said circumferential passage, a substantially imperforate cone-shaped member disposed adjacent said bottom wall with the apex thereof extending into said inner chamber, the surface of said member being spaced from said cylindrical member to permit flow communication between the chambers, and means for withdrawing said mercury through said cone member and said bottom wall.

3. In an amalgamating apparatus, an enclosed generally cylindrical casing including a bottom and side walls and a detachable top wall, a cylindrical bafile plate within said casing secured to said top wall and being spaced from said bottom wall and defining with said side wall an annular passage and further providing a concentric inner chamber, an inlet conduit in flow communication with said passage, a discharge conduit in fiow communication with said chamber, a coneshaped member in said chamber having the base thereof adjacent said bottom wall, said member being laterally spaced from said baflle plate in a horizontal plane defined by the bottom edge of the plate, means in said bottom wall providing access to the interior of said cone member, means in said cone-member providing access to said chamber, means for forcing material under pressure into said inlet and through the chamber,

and pressure regulating means for controlling the pressure in said passage and in said chamber 4. A device of the character described comprising a cylindrical casing including a top, bottom and side walls, a cylindrical bafile member within said casing defining an inner chamber and spaced from said side wall to define an annular passage therebetween, one end of said baflle member being immediately adjacent said casing top wall and the other end thereof being spaced from said casing bottom wall to provide for fiow communication between said annular passage and said chamber adjacent the bottom end of the latter, inlet means including a conduit opening into said annular passage, outlet means including a conduit extending through said passage and opening into said chamber, and a conical member mounted on said casing bottom wall with the apex thereof disposed above the lower end of said bafile member and the sides thereof spaced from the bafile member to define therewith a passage in flow communication with said annular passage and said chamber, and a plate member mounted on said cone adjacent the apex thereof with the general plane 7 of the. plate substantially normal to the axis of the cone.

'5. Apparatus for amalgamating a pulverized metal mixed with foreign matter in a liquid carrier including an enclosed cylindrical casing having a side wall, bottom wall and top wall, a cylindrical. member within said casing defining an inner chamber and an annular outer chamber, means defining a circumferentially extending passage between said inner and outer chambers adjacent said bottom wall, inlet means opening to said. outer chamber and vertically spaced from said bottom wall, discharge means in flow communication with said inner chamber and vertically spaced from said bottom wall, means for delivering said mixture to said inlet means under pressure, mercury disposed in said chamhers adjacent said bottom Wall and completely filling. said circumferential. passage, a substantially' imperforate cone-shaped member disposed adjacent said bottom wall with the apex thereof extending into said inner chamber, the surface of said member being spaced from said cylindrical member to permit flow communication between the chambers, and a dish-shaped 8 element secured to said member adjacent the apex thereof and provided with an aperture extending: therethrough.

ROBERT P. FISHER. ORVILLE E. WALIJNG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 53,805 Fuller Apr. 10,. 1866 63,221 Crosby Mar. 26, 1867 458,838 Pike Sept. 1, 1891 470,921 Shill Mar. 15, 1892 887,699 Sanford May 12, 1908 930,299 Luckenbach Aug, 3, 1909 1,127,845 Arnold Feb. 9, 1915 1,178,001 Edick et al. Apr. 4, 1916 1,616,784 Crosby Feb. 8, 1927 2,082,157 Grant June 1, 1937 2,347,284 Rotsler Apr. 25, 1944 OTHER REFERENCES Ore Dressing, by Richards, 1909, vol. III, page 1516. 

